1. Field of the Invention
The present invention relates to a sliding contact assembly and, in particular, to a system for collecting particles of abraded matter formed by the movement of a brush contact member along a contact slide track.
Sliding contact assemblies are used in apparatus to maintain electrical contact between two mechanically separate parts that are adapted to move relative to each other, where leads cannot be employed. One of the parts is provided with an extended contact track and the other of the parts is provided with a sliding contact member adapted to move relative to the contact track whilst maintaining an electrical contact with the track. Parts connected by sliding contact assemblies may move linearly or rotate relative to each other.
Sliding contact assemblies are used as components of known slip-ring systems where an electrical contact is maintained between a rotatably supported circular or annular contact track and a brush contact member adapted to slide along the track. The systems may be used for transmission of electrical signals, or for mere transmission of electrical energy.
The term brush contact member is here used to denote any sliding brush-shaped, wire-shaped, rod-shaped, or pin-shaped contact member that may be made of metal, conducting plastic material, carbon material, or any other material known in prior art for this purpose. Mechanical movement between the contact slide track and the brush contact member causes friction and so-called brush wear owing to an abrasion of small particles of electrically conducting contact material. These particles form fine dust that is scattered into the surroundings and deposited on other components including any insulating material surrounding the contacts. This may cause an appreciable deterioration of insulating properties and in turn may lead to short circuits or an erosion and burning away of the insulating material. Damage may be prevented by regular maintenance of sliding contacts assemblies, involving a careful removal of deposited material from various components, but some particular applications necessitate long periods of operation before maintenance becomes possible.
2. Description of the Prior Art
A slip-ring system for computer tomographs is disclosed in JP 06005340. Transmission of electrical energy is effected by means of a brush running along a ring. A separately disposed dust-collecting device comprises a collector for dust and a tube through which the dust is removed by suction.
A slip ring system for computer tomographs, as described in DE 195 43 383 B4, comprises a slip-ring contact track, and a brush holder and a contact brush adapted to slide along the contact track to form a sliding contact. The system further comprises at least one collecting device for capturing abraded particles that are formed during the movement. The collecting device is adapted to be electrostatically charged, so that captured abraded particles are retained in the collecting device by electrostatic forces.